Open source is GREAT, but developers must remember that the cost (time and $) to move from one version to another is very low....
Most of the Gnome developers probably are not Fedora users anyway, and why should they care which distro people use ? Similarly from a commercial perspective 'what's the business case ?'
As to distro switching - yes it isn't hard, and the desktop switching option in Fedora is even easier.
yum groupinstall "XFCE" set your desktop at gdm
End of problem
Alan